The present invention relates to a method of mounting, e.g., electronic parts onto a board.
When electronic parts are mounted on a board, a mounting position is corrected based on a position detection resulting from an optical method in order to obtain a certain accuracy of the mounting position. For this purpose, recognition marks are put on the board for recognizing the position of the board. At a mounting stage, recognizing this recognition mark sometimes produces a positional deviation, which is corrected during transporting the part by a transfer-head before an actual mounting.
There are various types of boards. One of them is a multiple printed board, i.e., multiple board blocks (unit boards) are formed in one single board. This multiple printed board is handled as a single board in a manufacturing process including mounting stages, then after the parts are completely mounted, the single board is divided into a plurality of printed wired assemblies. In this multiple printed board, relative positional accuracy of respective blocks with each other within the single board is not always obtained. Therefore, the recognition marks are provided in each block. The marks are recognized for mounting the parts.
In a conventional case, when the board undergoes plurality of mounting stages, and parts are sequentially mounted on the board, the recognition marks of each block are taken a shot by a camera at each stage. Therefore, the same marks are recognized many times, which makes a total recognition time long. As a result, it has been an obstacle to the improvement of mounting efficiency.
The present invention addresses the problem discussed above, and aims to provide a part-mounting method which can shorten a board-position-recognition-time, thereby improving the mounting efficiency.
A part-mounting-method of the present invention mounts sequentially parts onto a plurality of blocks (unit boards) formed on a single entire board at a plurality of mounting stages. The method comprises the following steps:
(a) at a first mounting stage, recognizing every recognition point formed on a single entire board, thereby obtaining relative positional data of each recognition point formed in the single entire board;
(b) at a second stage and onward, recognizing particular recognition points, thereby detecting a whole position of the single entire board with respect to respective stages;
(c) based on this whole position and the relative positional data, detecting a positional deviation of a board block at respective stages; and
(d) correcting the positional deviation and mounting the parts onto the board block.
Another method of the present invention also mounts sequentially parts onto a plurality of blocks (unit boards) formed on a single entire board at a plurality of mounting stages. The method comprises the following steps:
(a) at a particular stage, recognizing the following three kinds of recognition points: (a-1) particular recognition points of a single entire board, (a-2) recognition points of a target board block of this particular stage and (a-3) recognition points of another target board block of downstream stage from this particular stage, thereby obtaining relative positional data of respective recognition points of the target board blocks with respect to the particular recognition points;
(b) at the downstream stage from the particular stage, recognizing the particular recognition points only, thereby detecting a whole position of the single entire board;
(c) based on the whole position and the relative positional data discussed above, detecting a positional deviation of the target board block at the downstream stage; and
(d) correcting the positional deviation and mounting the parts onto the board block.
According to these methods, at the particular mounting stage in the upstream, particular recognition points of the single entire board and the recognition points of the target board blocks in the downstream are recognized. Thus the relative positional data of the respective recognition points in the target board blocks with respect to the particular recognition points are obtained. At the downstream mounting stage, therefore, only the particular recognition points are recognized for detecting the whole position of the single entire board. Based on the whole position and the relative positional data, a positional deviation of the target board block of an active mounting stage is detected. Then the positional deviation is corrected before the parts are mounted onto the target board block. As such, a disadvantage of the conventional method, i.e., a recognition points are repeatedly recognized, is overcome, and a total recognition time can be shortened.